Leaves (emission) from point
Select your leaf on second layer and go to Edit mode.
Select bottom face and hit Shift + S > Cursor to Selected.





Go back to Object mode and hit CtrlShiftAlt + C > Origin to 3D cursor.




That's all.

If you want, you can select only two bottom vertices and do the rest same as above.

Or you can even manually position 3D cursor, it's up to you.